How do consumers judge what is authentic and what signals authenticity?

Social media is big business, but as companies are trying to jump into this arena many are using questionable practices. Take this LA Times article for example (http://ow.ly/Cv6F) concerning professional bloggers who are essentially accepting bribes from companies in exchange for positive WOM. Consumers are becoming savvy and companies who engage in these practices are being met with backlash (such as boycott groups on Facebook and Twitter). Although the government has responded with new disclosure regulations, they are fuzzy and unclear and may do little.

Authenticity will become a very important component of social media. Important research questions need to be addressed, such as: What are the signals authenticity? How do consumers judge authentic from inauthentic?